CN1598919A - Organic luminous display panel and its feedback control device - Google Patents
Organic luminous display panel and its feedback control device Download PDFInfo
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- CN1598919A CN1598919A CNA031581803A CN03158180A CN1598919A CN 1598919 A CN1598919 A CN 1598919A CN A031581803 A CNA031581803 A CN A031581803A CN 03158180 A CN03158180 A CN 03158180A CN 1598919 A CN1598919 A CN 1598919A
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- Prior art keywords
- organic light
- voltage
- display panel
- light emitting
- control system
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Abstract
The invention relates to an organic luminous display panel and its feed back control system. It takes advantage of the feed back control system, emulates and reflects the aging status of the components, drives one of the voltage resource of the OLED in the organic luminous display panel and compensates it with the aging of the components in order to strengthen the efficiency and useful life of the luminous active display panel.
Description
Technical field
The present invention is relevant for two-d display panel, particularly relevant for a kind of organic electroluminescence display panel and feed back control system thereof, can be by the degree of aging of feed back control system emulation organic light emission list, so that organic electroluminescence display panel can be kept stable luminosity, be not subjected to the aging influence of assembly.
Background technology
Organic Light Emitting Diode (Organic Light Emitting Diode; OLED) display panel is a kind of thin film lamination escope that utilizes organic compound as luminescent material, has that face is luminous, an autoluminescence, slim, advantages such as amount is light, low driving voltage.The OLED display panel can be distinguished into active formula (active matrix) and two kinds of passive types according to its type of drive, and wherein active formula OLED (AM-OLED) panel is to use thin film transistor (TFT) (thin film transistor mostly; TFT) come driving OLED to show.
Fig. 1 represents the structural drawing (is example with 4 display unit 16a-16d) of Organic Light Emitting Diode (OLED) display panel, the sweep signal on scanning code translator (scanning decoder) the 12 driven sweep line 20a-20b; Data-signal on data driver (data driver) the 10 driving data lines 18a-18b; A plurality of organic luminescence display unit 16a-16d place sweep trace and data line infall respectively, and functionally be coupled to wherein a sweep trace and data line wherein, provide sweep signal and the addressing organic luminescence display unit can write among the organic luminescence display unit 16a-16d data-signal of data line by sweep trace.
Fig. 2 is the structural drawing of conventional OLED display unit, is example at this with organic luminescence display unit 16a.Organic luminescence display unit 16a has switching transistor 22a, driving transistors 24a, capacitor 26a and Organic Light Emitting Diode 28a.When the sweep signal of sweep trace 20a was enabled, switching transistor 22a was conducting, made the signal of data line 18a be able to be stored among the capacitor 26a by switching transistor 22a, and capacitor 26a comes the storage data signal in the mode of voltage.Driving transistors 24a is serially connected with OLED 28a, and both are arranged at high voltage node V again
DDWith lower voltage node V
SSBetween.Driving transistors 24a is according to the voltage that capacitor 26a deposited that its grid coupled and conducting, in order to do to provide OLED 28a luminous required electric current.
The OLED display panel (person as shown in Figure 1, 2) that tradition adopts amorphous silicon film transistor (α-Si TFT) to drive is because driving transistors 24a is in conducting state for a long time, so its threshold voltage (threshold voltage) V
ThAlso can rise gradually thereupon; In addition, Organic Light Emitting Diode 2 8a under long operation its its on voltage V
OLEDAlso can increase; As shown in Figure 3.Thus, the electric current that will cause flowing by Organic Light Emitting Diode 28a reduces, and causes the luminous brightness of Organic Light Emitting Diode 28a to diminish.Along with oled panel increases service time, the brightness step-down of each organic luminescence display unit, the brightness of whole OLED display panel is decay and then, so influence the usefulness performance of OLED display panel, has also reduced its serviceable life.
Please refer to Fig. 2, the electric current I of the described driving transistors 24a that flows through
DsIts value is:
I
ds＝K(V
GS-V
th)
2＝K(V
G-V
S-V
th)
2；
Wherein, V
S=V
SS+ V
OLEDD, K is a constant, so I
Ds=K (V
G-V
SS-V
OLED-V
Th)
2So the OLED display panel is under the process long-time operation, because the assembly catabiosis causes threshold voltage V
ThAnd OLED 28a voltage V on it
OLEDIncrease, must make drive current I
DsDescend, and cause the luminosity of OLED display panel to decay.
Summary of the invention
In view of this, a purpose of the present invention is used for the electric current of steady flow through organic light-emitting units for proposing a kind of feed back control system, to avoid because of the aging luminosity decay that is caused of assembly of driving transistors and OLED and the problem that shortens serviceable life.
Another object of the present invention is for proposing a kind of organic electroluminescence display panel, use described feed back control system, make one of voltage source that drives OLED in the described organic electroluminescence display panel, can compensate along with the degree of aging of assembly, in order to do showing and serviceable life with the usefulness of promoting described organic electroluminescence display panel.
For realizing purpose of the present invention, the feed back control system that the present invention proposes, be applicable to organic light-emitting units, described organic light-emitting units is arranged between one first voltage node and one second voltage node, and comprises one first Organic Light Emitting Diode (OLED) serial connection, one the first transistor at least.Feed back control system of the present invention, comprise: a simulator has one the 2nd OLED and is connected in series a transistor seconds, described first and second OLED and described first and second transistors use the same process condition to make and get, and are used to reflect the degree of aging of described organic light-emitting units; And a constant current source couples the other end and described second voltage node of described simulator, and the electric current that is used to described the 2nd OLED is circulated keeps certain, with this voltage of described Section Point is reduced along with the degree of aging of described organic light-emitting units.
For realizing another object of the present invention, the organic electroluminescence display panel that the present invention proposes is mainly used described feed back control system, comprising: a plurality of organic light-emitting units, and each described organic light-emitting units is arranged between first and second voltage nodes; Feed back control system, the degree of aging of the described organic light-emitting units of emulation, and the voltage of described Section Point is reduced along with the degree of aging of described organic light-emitting units.
Description of drawings
Fig. 1 represents the structural drawing of OLED display panel.
Fig. 2 represents the structural drawing of conventional OLED display unit.
Fig. 3 represents that voltage and transistorized threshold voltage on its of OLED are with graph of a relation that service time, lengthening increased.
Fig. 4 represents that feed back control system of the present invention is applied to the synoptic diagram of organic light-emitting units.
Fig. 5 represents that the present invention uses the system schematic of mu balanced circuit.
Fig. 6 represents to use the OLED display panel of feed back control system of the present invention.
Fig. 7 A-7C represents V
OLED+ V
Th, V
XAnd V
SSThe graph of a relation of corresponding service time.
Symbol description
10-scans code translator; The 12-data driver; The 14-OLED display panel;
The 16a-16d-organic luminescence display unit; The 18a-18b-sweep trace;
The 20a-20b-data line; The 22a-switching transistor; The 24a-driving transistors;
26a-electric capacity; The 28a-Organic Light Emitting Diode; The 30-simulator;
30a-OLED; The 30b-transistor; The 40-feed back control system;
The 32-mu balanced circuit; The 34-constant current source;
42～amplifier; The 44-bipolar junction transistor; The 46-resistor.
Embodiment
For described purpose of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly, and conjunction with figs. are described in detail below.
Narrate as can be known the electric current I of the described driving transistors 24a that flows through with reference to Fig. 2 and corresponding derivation thereof
DsIts value is:
I
ds＝K(V
G-V
SS-V
OLED-V
th)
2；
So, after organic light-emitting units is aging, V
OLEDAnd V
ThIncrease can cause drive current I really
DsDescend.Therefore, the present invention mainly designs a feed back control system, makes V
SSCan be along with V
OLEDAnd V
ThIncrease and reduce so that V
SS+ V
OLED+ V
ThBecome certain value, so drive current I
DsJust can keep initial set value, then the brightness of OLED just can not decay.
Fig. 4 represents that feed back control system of the present invention is applied to the synoptic diagram of organic light-emitting units.
Feed back control system 40 of the present invention is used for the electric current of steady flow through an organic light-emitting units 16a, and described organic light-emitting units 16a is arranged at has voltage V
DDOne first voltage node and have a voltage V
SSOne second voltage node between, the structure of organic light-emitting units 16a and running are no longer given unnecessary details above cooperating Fig. 2 to describe in detail at this.Among Fig. 4, described feed back control system 40 comprises: a simulator 30, and a constant current source 34.
Described simulator 30 comprises that an Organic Light Emitting Diode (OLED) 30a is connected in series a transistor 30b, OLED 30a in OLED 28a among the described luminescence unit 16a, transistor 24a and the simulator 30, transistor 30b use the same process condition make and MOS transistor and OLED, for example for α-Si TFT technology but be not limited to this.
Described simulator 30 is coupled to described the 3rd node and (has voltage V
DD) and described constant current source 34 between.What be worth notes is that the grid of described transistor 30b receives a predetermined bias or voltage drive (stress) V
Stress, and drive described OLED 30a circulating current I
1, to reflect transistor 24a among the described organic light-emitting units 16a and the degree of aging of OLED 28a.
Because described constant current source 34 couples described simulator 30, described OLED 30a circulating current I
1Can become predetermined initial current I, that is the steady current that provided of constant current source 34, and node voltage V
X, pairing current potential when inducing transistor 30b and OLED 30a circulating current I naturally.Under operating for a long time, be subjected to V
StressWith transistor 30b and the aging influence of OLED 30a, the threshold voltage V of transistor 30b
ThWith voltage V on its of OLED 30a
OLEDWill increase (please refer to shown in the 7A figure).In order to allow described electric current I
1Keep fixing initial current I, so the related node voltage V that causes
XDescend in (shown in 7B figure).The present invention is with node voltage V
XCouple to the described second voltage node (V
SS), Section Point voltage (V then
SS) really can be along with node voltage V
XDecline and descend (shown in 7C figure).In this way, V
SSCan be along with V
OLEDAnd V
ThIncrease and reduce, reach the described V of making
SS+ V
OLED+ V
ThBecome the purpose of certain value, so drive current I
DsJust can keep initial set value, then the brightness of OLED just can not decay.Wherein, the ordinate unit of described Fig. 7 A-7C is volt V, and horizontal ordinate unit is hour (hr).
In this embodiment, node voltage V
XMore can couple to the described second voltage node (V by a mu balanced circuit 32
SS).Fig. 5 represents to use the system schematic of mu balanced circuit 32.Mu balanced circuit 32 shown in Figure 5 is used to become a voltage source and is coupled to the second voltage node (V by the voltage follower (voltage follower) that amplifier 42, PNP bipolar junction transistor 44 and resistor 46 are constituted
SS) use.
Fig. 6 represents to use the OLED display panel (is example with 4 organic light-emitting units) of feed back control system of the present invention.Organic electroluminescence display panel of the present invention (Fig. 6) can influence brightness because of assembly is aging, comprising: a plurality of organic light-emitting units 16a-16d, the structure of each described organic light-emitting units as described the 1st, 2 figure and narrate in describe in detail, do not repeat them here; Scanning code translator 12; Data driver 10; And described feed back control system 40 couples the second voltage node (V of each organic light-emitting units (16a-16d)
SS), so that the voltage of described Section Point reduces along with the degree of aging of described organic light-emitting units, and then reach the problem that OLED display panel luminosity reduces and reduce serviceable life of avoiding.
The present invention with a preferred embodiment openly as above; so it is not to be used to limit the present invention, and any those skilled in the art are under the situation that does not break away from the spirit and scope of the present invention; can change and modification, so protection scope of the present invention is as the criterion with the claim restricted portion that is proposed.
Claims (8)
1. feed back control system, be used for the electric current of steady flow through an organic light-emitting units, described organic light-emitting units is arranged between one first voltage node and one second voltage node, comprises that at least one first Organic Light Emitting Diode is connected in series a first transistor, and described feed back control system comprises:
One simulator, an end couple a tertiary voltage node, comprise that one second Organic Light Emitting Diode is connected in series a transistor seconds, and described first and second Organic Light Emitting Diodes and described first and second transistors use the same process condition to make and get; Wherein, described transistor seconds receives a predetermined bias, and drives the described second Organic Light Emitting Diode circulating current, to reflect the degree of aging of described organic light-emitting units;
One constant current source, couple the other end and described second voltage node of described simulator, the electric current that is used to described second Organic Light Emitting Diode is circulated keeps certain, with this voltage of described Section Point is reduced along with the degree of aging of described organic light-emitting units.
2. feed back control system as claimed in claim 1, wherein, described first and second transistors are MOS transistor.
3. feed back control system as claimed in claim 2, wherein, described first and second transistors are the Thin Film MOS transistor.
4. feed back control system as claimed in claim 3, wherein, described first and second transistors use amorphous silicon (the thin-film technique manufacturing of α-Si) and getting.
5. an organic electroluminescence display panel can not influence brightness because of assembly is aging, comprising:
A plurality of organic light-emitting units, each described organic light-emitting units are arranged between one first voltage node and one second voltage node, comprise that at least one first Organic Light Emitting Diode is connected in series a first transistor; Wherein, the voltage of described first voltage node is greater than the voltage of Section Point;
One feed back control system comprises at least:
One simulator, an end couple a tertiary voltage node, comprise that one second Organic Light Emitting Diode is connected in series a transistor seconds, and described first and second Organic Light Emitting Diodes and described first and second transistors use the same process condition to make and get; Wherein, described transistor seconds receives a predetermined bias, and drives the described second Organic Light Emitting Diode circulating current, to reflect the degree of aging of described organic light-emitting units; And
One constant current source, couple the other end and described second voltage node of described simulator, the electric current that is used to described second Organic Light Emitting Diode is circulated keeps certain, with this voltage of described Section Point is reduced along with the degree of aging of described organic light-emitting units.
6. organic electroluminescence display panel as claimed in claim 5, wherein, described first and second transistors are MOS transistor.
7. organic electroluminescence display panel as claimed in claim 6, wherein, described first and second transistors are the Thin Film MOS transistor.
8. organic electroluminescence display panel as claimed in claim 7, wherein, described first and second transistors use amorphous silicon (the thin-film technique manufacturing of α-Si) and getting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031581803A CN1598919A (en) | 2003-09-16 | 2003-09-16 | Organic luminous display panel and its feedback control device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031581803A CN1598919A (en) | 2003-09-16 | 2003-09-16 | Organic luminous display panel and its feedback control device |
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| Publication Number | Publication Date |
|---|---|
| CN1598919A true CN1598919A (en) | 2005-03-23 |
Family
ID=34660410
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA031581803A Pending CN1598919A (en) | 2003-09-16 | 2003-09-16 | Organic luminous display panel and its feedback control device |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101313631B (en) * | 2005-11-25 | 2010-09-08 | 松下电工株式会社 | OLED driver and illuminator equipped with such driver |
| CN101231815B (en) * | 2007-01-23 | 2010-09-22 | 立锜科技股份有限公司 | Energy saving control circuit of organic luminous panel and method thereof |
| CN101582237B (en) * | 2008-05-16 | 2011-06-29 | 群康科技(深圳)有限公司 | Pixel structure and organic light-emitting diode display |
| CN109215580A (en) * | 2018-09-18 | 2019-01-15 | 昆山国显光电有限公司 | Image element circuit structure and its driving method |
-
2003
- 2003-09-16 CN CNA031581803A patent/CN1598919A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101313631B (en) * | 2005-11-25 | 2010-09-08 | 松下电工株式会社 | OLED driver and illuminator equipped with such driver |
| CN101231815B (en) * | 2007-01-23 | 2010-09-22 | 立锜科技股份有限公司 | Energy saving control circuit of organic luminous panel and method thereof |
| CN101582237B (en) * | 2008-05-16 | 2011-06-29 | 群康科技(深圳)有限公司 | Pixel structure and organic light-emitting diode display |
| CN109215580A (en) * | 2018-09-18 | 2019-01-15 | 昆山国显光电有限公司 | Image element circuit structure and its driving method |
| CN109215580B (en) * | 2018-09-18 | 2020-05-05 | 昆山国显光电有限公司 | Pixel circuit structure and driving method thereof |
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